Card Range To Study

7 Cards in this Set

Front

Back

What are some limitations of sampling?

- there are many different ways that you can pick your sample, but not many will allow direct generalisations to the entire population
- Regardless of how 'big' your sample is, if it is chosen badly or inadequately covers the general population, it remains a biased sample and this will need to be recognised

- Each person within the population of interest has an equal chance of being selected for the study
- Does not ensure that the characteristics of the sample & population will coincide exactly, but can be used with statistics to determine the range within which they are the same
- Number of ways to do this, but often involves a computer program picking random numbers which match up to assigned numbers for the population

What is Systematic sampling?

- Using a predetermined system to pick participants
- Usually requires a list of partcipant, and you invite every nth person to be involved in the project
- If the list is not arranged in a particular order (e.g. alphabetically) can be considered equivalent to random sampling.

What is Cluster sampling?

- The unit of sampling is a group (or cluster) of people rather than individuals
- Clusters may include villages, apartment buildings, classes, families etc
- Convenient method that has a problem because often 'like people stick together'

What is Snowball (chain referral)sampling?

- People who meet the criteria for inclusion in a study are asked to name others they know whom also fit the criteria for inclusion.
- Can be useful to identify hard-to-find individuals (e.g. those with illegal behaviours, homeless people etc)

What is Convenience sampling?

- People chosen because the investigator presumes that they are typical of the population
- Often chosen in a haphazard fashion, or because that they are 'handy' or easy to obtain
- Often find researchers will approach only people that they do not feel threatened by, believe may be interested in the research etc
- rarely reflect the true population
- important to think about how truly your sample might reflect the actual population and discuss this